The role of pheromones in guiding American eel migration

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The role of pheromones in guiding American eel migration

Populations of American eels have declined throughout their historic range along the Atlantic coast.  Contributing to these declines is the effects of dams and other barriers blocking their migration from the Sargasso Sea to freshwater as juveniles and from freshwater back to the Sargasso Sea as adults where they return to spawn.  Small, juvenile eels are unable to bypass barriers and cannot access critical upstream habitat, and out-migrating reproductive adults suffer high mortality at dam turbines.  Researchers at the USGS Northern Appalachian Research Laboratory (NARL) have been collaborating with partners at the USGS Great Lake Science Center and Michigan State University to develop methods for restoring eel populations.  NARL scientists are investigating the role of pheromones, odors emitted from other eels in the water column, as a communication tool used by migrating eels.  Odors eliciting an attraction to eels could be identified, synthesized, and potentially utilized in combination with other fish passage technologies (e.g., fish ladders, electrical guidance, attraction flows) to provide an effective and sustainable method to guide eels to safe passage and thereby enhance restoration. 

Elver stage American eel, Anguilla rostrata

Migratory elver-stage (juvenile) American eel collected from the Chesapeake Bay for use in pheromone studies.

(Credit: Julie Devers, U.S. Fish and Wildlife Service. Public domain.)

Laboratory pheromone bioassay for glass stage American eels

NARL Ecologist, Carrie Blakeslee, is conducting a laboratory bioassay on the attraction of various pheromones to glass-stage American eels.  Due to eel’s nocturnal nature, laboratory tests must be completed at night using red light.

(Credit: Heather Galbraith, USGS Leetown Science Center. Public domain.)